Pneumatic hammer, drilling machine, and the like



Feb. 5, 1924. 1,482,507

E. COHN PNEUMATIC HAMMER, DRILLING MACHINE, AND THE LIKE Filed June 3. 1922 Jn ventor;

Patented Feb. 5, lg d.

UNETED EMIL conn, or BERLIN, GERMANY.

PNEU IMATIC HAMMIEB, DRILLING MACHINE, AND THE LIKE.

Application filed June 3,

To all whom it may concern Be it known that I, EMIL Conn, citizen of the United States of North America, residing at Markgrafenstrasse 27, Berlin, Germany, have invented certain new and useful Improvements in and Relating to Pneumatic Hammers, Drilling Machines, and the like; and I do hereby declare the following to be a full, clear, and exact description of the invention, of which the following is a specification.

The invention relates to that class of pneumatic hammers, drilling machines and the like fitted with motor drives or with means for connecting them to electric drives, by means for connecting them to electric drives, by means of which a compressor piston arranged within the cylindrical hammer casing is actuated, said compressor piston working above a piston striker and accelerating the latter during the compression stroke so that it strikes upon the tool during the suction stroke however drawing the piston striker up and returning it; In comparison with the known devices of this kind, whereby the compressed air produced by the compressor piston is made to act directly and speedily upon the striker piston at the same time accelerating it, the characteristic feature of the present invention consists therein that without the provision of a special automatic or positively controlled valve in the first instance the compressed air isproduced by the compressor piston within a compressor cylinder arranged above the piston striker, until a certain pressure is reached, whereupon in a certain position of the compressor piston the air overflows into that part of the cylinder in which the piston striker is work ing so that the latter is hit by the pressure of the highly compressed air and is suddenly accelerated in a very effective manner.

A further achievement thereof is that the intensity of the blow can be regulated within wide ranges, as for instance by a throttling of the suction openings in the compressor cylinder the quantity of air drawn in can be regulated within it and thereby the pressure of the quantity of compressed air at which the overflow into the cylinder of the piston striker takes place.

Upon the accompanying drawing, one mode of carrying out the invention is shewn 1822. Serial No. 565,702.

by way of example. in Fig. 1 in a section and in Fig. 2 in a front view.

The operator takes hold of the machine with the right hand by the handle 1, and with the left hand by the cover 2 of the hammer in order to guide the latter. In the hammer casing, divided into two cylinders by an intermediary ring 3, on the one hand the compressed air piston 4 and on the other hand the piston striker 5 is guided. The cylinder 6 for the compressed air piston is of a larger diameter than the cylinder 7 for the piston striker. The compressed air piston i is driven by means of a connecting rod 8 for an electric motor arranged within the hammer handle or from a wheel gearing. The piston draws in the air through openings, 9 of the cylinder 7 and controllable openings 10 of the hammer cover 2. By means of the cylindrical projection 11 the compressed air piston is closely guided in the intermediary ring 3 so that the compression space forms a kind of cylindrical space. Between the cylindrical projection 11 and the piston 4 a recessed portion 12 has been provided for. If the piston is advanced to such an extent that the recessed portion 12 lies opposite to the intermediary ring 3, the compressed air passes from the cylinder space 6 into the cylinder 7 above the piston striker and accelerates the latter thereby suddenly expanding. If the piston striker 5 has been thrown forward suffi ciently far, it will uncover the outlet opening 18 in the cylinder 7 so that the expanded air can escape completely. Upon the piston striker hitting the coiled spring 14 in the mouth piece 15 it rebounds so that in the first instance the outlet openings 13 are closed again, whereupon in consequence of the suction stroke of the piston a the piston striker is also drawn up and the cycle of operations can start afresh. The intensity of the blow can be regulated by the degree of the air pressure within the cylinder 6 which is effected by adjusting the throttling of the holes 10.

I claim as my invention:

Mechanical pneumatic hammer, drilling tool or percussion tool arranged to have a motor drive or an electrical drive to be connected therewith, characterized by a cylindrical hammer casing, a compressor piston and hammer piston cooperating therewith, In testimony whereof I have signed my and an intermediary ring within the oylinname to this specification in the presence of 10 drical hammer casing, said ring dividing two subscribing witnesses.

said easing into two chambers, the said compressor piston being provided with a groove EMIL COHN.

for the passage of the pie-compressed air Witnesses: i

from the compression chamber into the ham- ARTHUR SoHRoEDER, iner piston chamber. EMORY H. LORD. 

